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author | Dan Williams <dan.j.williams@intel.com> | 2017-04-06 16:04:31 (GMT) |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-04-21 07:31:20 (GMT) |
commit | a9826aa4860a9ca1268a9ab5c10fc5e65a72b4ef (patch) | |
tree | 03ad2ed6cac63a5e6fc7187545be9dcfb1e651f5 /arch/hexagon | |
parent | 59bf2308895337fdf70b3a183e7f3c8723030982 (diff) | |
download | linux-a9826aa4860a9ca1268a9ab5c10fc5e65a72b4ef.tar.xz |
x86, pmem: fix broken __copy_user_nocache cache-bypass assumptions
commit 11e63f6d920d6f2dfd3cd421e939a4aec9a58dcd upstream.
Before we rework the "pmem api" to stop abusing __copy_user_nocache()
for memcpy_to_pmem() we need to fix cases where we may strand dirty data
in the cpu cache. The problem occurs when copy_from_iter_pmem() is used
for arbitrary data transfers from userspace. There is no guarantee that
these transfers, performed by dax_iomap_actor(), will have aligned
destinations or aligned transfer lengths. Backstop the usage
__copy_user_nocache() with explicit cache management in these unaligned
cases.
Yes, copy_from_iter_pmem() is now too big for an inline, but addressing
that is saved for a later patch that moves the entirety of the "pmem
api" into the pmem driver directly.
Fixes: 5de490daec8b ("pmem: add copy_from_iter_pmem() and clear_pmem()")
Cc: <x86@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/hexagon')
0 files changed, 0 insertions, 0 deletions